Liquid handling and dispensing apparatus

ABSTRACT

A tank of the type including an entrapped air cushion and for receiving, heating and dispensing heated liquid is improved through the combination of two cooperating liquid carrying conduits enclosed within the tank. A first of such conduits provides for preheating of incoming liquid and discharge into a lower portion of the tank. The second conduit, which draws cooler liquid from the lower portion of the tank for discharge into a mixing chamber, includes a vent in its location in the upper portion of the tank to control the liquid level in the tank. The mixing chamber receives cooler liquid from the second conduit and communicates with the upper portion of the tank to receive heated liquid, discharging a mixture of the two through a liquid discharge means.

United States Patent Inventor William C. Knox Jr.

46 Des Molnes Way South, Seattle, Wash. 98148 Appl. No. 835,292

Filed June 2, 1969 Patented Feb. 23, 1971 LIQUID HANDLING AND DISPENSING3,503,384 3/1970 Matarazzo et al.

ABSTRACT: A tank of the type including an entrapped air cushion and forreceiving, heating and dispensing heated liquid is improved through thecombination of two cooperating liquid carrying conduits enclosed withinthe tank. A first of such conduits provides for preheating of incomingliquid and discharge into a lower portion of the tank. The secondconduit, which draws cooler liquid from the lower portion of the tankfor discharge into a mixing chamber, includes a vent in its location inthe upper portion of the tank to control the liquid level in the tank.The mixing chamber receives cooler liquid from the second conduit andcommunicates with the upper portion of the tank to receive heatedliquid, discharging a mixture of the two through a liquid dischargemeans.

g z ii PATENTEDFEBNIBYI 3.565045 I SHEET 2 OF 2 INVENTOR.

WILLIAM c. KNOXJR.

n-rTonNiV- uoum HANDLING AND DISPENSING APPARATUS The heating anddispensing of heated liquids, such as water, in certain types ofvehicles and conveyances, for example, aircrafts, trains, boats, mobilehomes, camping trailers, etc., present problems difierent from theperformance of such functions within stationary heated enclosures suchas buildings. Generally, such vehicles are designed to be compact and tomake as efficient utilization of space as possible. When the combinationof weight and space is important, as is the case in aircraft either inlavatories or for heating water for other purposes, apparatus to heatand dispense water preferably is very small and hence cannot storeappreciable amounts of heated water. For example, such apparatuscommonly in use in large jet passenger aircraft has a liquid storagecapacity of no more than about a gallon. Such apparatus must have thecapability of heating liquid rapidly yet of dispensing heated liquid ata temperature which is not too hot for reasonable passenger use. Oneexample of such use is the rinsing of hands.

This type of apparatus must depend upon a larger liquid storage tankwhich supplies liquid. to the heating and dispensing unit as required.Frequently, such a tank and its supply passages will include or gatherentrapped air. If introduced into a relatively small heating anddispensing apparatus such entrapped air can result in sputtering orspraying of the fluid discharged.

As a result of the small size of the apparatus to which the presentinvention relates, there is a danger of either Stratification of liquidat different temperatures or the flow of relatively cold inlet liquiddirectly to the means which is intended to discharge heated liquid. insome cases, excessively hot liquid, which has collected near the top ofthe unit,has been known to be discharged directly for use; In othercases, unheated liquid has been discharged directly.

Because the liquid heating and dispensing apparatus may be assembled ina vehicle which is parked at temperatures below the freezing point ofthe liquid retained in the apparatus, means must be provided to allowfor expansion of frozen liquid.

It is a principal object of the present invention to provide an improvedapparatus for heating and dispensing heated liquid of the type describedabove, which avoids stratification of heated liquid in the apparatus andavoids direct communication between means to discharge heated liquid andincoming cooler liquid which may include entrapped gases.

Another object is to provide such an apparatus with means to preheatincoming cooler liquid and to draw independently such preheated liquidintroduced into the tank for mixture with heated liquid from the tankwithout drawing entrapped air carried by the incoming liquid.

Still another object is to avoid discharge from the tank of liquid atthe highest temperature level in the tank.

These and other objects and advantages will be more fully understoodfrom the following detailed description and the drawings all of whichare intended to be representative of rather than limiting on the scopeof the present invention In the drawings:

FIG. 1 is a partially sectional view of the improved liquid heating anddispensing apparatus according to a preferred form of the presentinvention;

FIG. 2 is a sectional view of the apparatus of FIG. 1 along line 2-2;

FIGS. 3, 4 and 5 are fragmentary sectional views of the first liquidcarrying conduit including the pumping means,

The present invention relates to the type of liquid handling anddispensing apparatus described in copending application Ser. No.681,031, now US. Pat. No. 3,447,560 filed Nov. 11, 1967 as acontinuation of application Ser. No. 524, 194, filed Feb. I, 1966 andnow abandoned. It has been recognized that the above objects,particularly with respect to efficiency of operation, preheating andavoidance of Stratification and of direct communication between inletliquid and the discharge means can be accomplished as a significantimprovement over prior apparatus. According to the present invention,this is done through the use, in combination, of two liquid carryingconduits both enclosed within the tank and only one of whichcommunicates directly with incoming liquid.

A first liquid carrying conduit, which introduces liquid into the tank,preferably enters in the tank lower portion which is generally cooler.ln such an arrangement, it then passes in what might be considered to bea loop from the lower portion of the tank into the upper portion andthen returns to the lower portion to discharge incoming, and at thatpoint preheated, liquid generally at the lower wall of the tank. Suchtype of discharge avoids turbulent flow through the tank. It isimportant that the first liquid carrying conduit include in its locationin the upper portion of the tank, either through the loop arrangement orupon entry in that area, a pumping means, such as an aspirator orventuri. Such pumping means and a cooperating port means draws heatedliquid from the top of the tank into the first liquid carrying conduitto mix with and preheat the incoming liquid. In a preferred embodiment,the preheating process is a combination of two sources: a first is heatfrom liquid carried by the tank conducted through walls of the firstliquid carrying conduit into the incoming liquid; a second and moreimportant is the mixing as a result of operation of the pumping means ofhotter liquid in the upper portion of the tank with the incoming liquidfor subsequent discharge into the lower portion of the tank.

The second liquid carrying conduit has its inlet within the tank in thelower portion in order to draw cooler liquid for more efiicient use inmixing with hotter liquid in a final mixing chamber connected betweenthe second liquid carrying conduit and a liquid discharge means. Thesecond liquid carrying conduit also includes in its location in itsupper portion of the tank a level control vent. Such vent establishesthe minimum liquid level in the tank at a point above the port meanscooperating with the pumping means of the first liquid carrying conduitto assure the availability of hot liquid for use in preheating incomingliquid.

Separation between the outlet of the first conduit and the inlet of thesecond conduit allows entrapped gases, such as air, from the incomingliquid, to rise in the tank. Such gases coilect at the top, allowing formore uniform control and bleeding of such entrapped air and avoidingsputtering or spraying of the discharged liquid.

Referring to FIGS. 1 and 2, the apparatus of the present inventionincludes a tank shown generally at 10 having an upper portion 11enclosed by a wall 12 and a lower portion 13 enclosed by a wall 14. Theupper portion has an upper wall 16 and the lower portion has a lowerwall 18 generally defining the top and bottom, respectively, of thetank. However, for convenience of manufacture or installation, the tankshell can assume a variety of shapes.

Mounted within the tank are first liquid carrying conduit 20 and secondliquid carrying conduit 22. The first conduit enters through a wall ofthe tank, preferably in the lower portion, for example, through lowerwall 18 and, in FIGS. 1 and 2, fitting 21. In the embodiment shown inFIG. 1, it. then extends in a loop from the lower portion into the upperportion returning to the lower portion for discharge through firstconduit outlet 24. In order to avoid turbulent flow within the tank as aresult of the incoming liquid, the first conduit outlet 24 directs theincoming liquid generally toward or along lower wall-18.

The first conduit 20 includes in its location in the upper portion ofthe tank first conduit pumping means 26 which cooperates with firstconduit port means 28 to draw heated liquid from the upper portion ofthe tank for mixing with and preheating the incoming liquid. The firstconduit can enter the tank directly into the upper portion therebyrelying for preheating on the pumping means and on conduction throughthe conduit wall as it passes to the lower portion. Such preheatingassists in avoiding stratification within the tank and also makes moreefficient use of the heated liquid generated in the tank. It ispreferable that the walls of the first conduit are of a heat conductingmaterial such as a metal. In such a case, preheating of the incomingliquid as a result of mixing through the pumping means and thecooperating first conduit port means is enhanced through conduction ofheat from heated liquid in the tank through walls of the first conduitto the incoming liquid. Thus, incoming liquid first discharged into theinterior of tank from first conduit is at a temperature substantiallygreater than that of the liquid first entering the first liquid carryingconduit 20. By increasing the incoming liquid temperature closer to thefinal desired temperature, the possibility of stratification in the tankis reduced and more uniform heating can take place.

The second liquid carrying conduit 22, like the first liquid carryingconduit 20, is enclosed within tank 10. The second conduit inlet 30 islocated in the lower portion of the tank to draw the preheated yetcooler liquid from the tank for subsequent mixing with heated liquid infinal mixing chamber 32. Second conduit inlet 30 is spaced apart fromfirst conduit outlet 24 to allow entrapped gases such as air in incomingliquid to rise through the tank toward the top and to allow some mixingof the incoming liquid with liquid already in the tank. In this way, theliquid first introduced into the tank does not flow directly into thesecond conduit thus reducing the possibility of direct flow between theliquid inlet 34 and the liquid discharge means 36. To enhancecirculation in the bottom of the tank and to allow for complete tankdrainage, if such is desired, an auxiliary circulation and drain port 31can be provided. Such port 31 can be placed through fitting 21 intocommunication with conduit 20 and positioned to direct liquid along thelower wall 18.

The second conduit extends from the lower portion of the tank into theupper portion of the tank discharging at 38 into final mixing chamber32. The second conduit includes a liquid minimum level control vent 40located in the upper portion of the tank at a point vertically higherthan the first conduit port means 28 to maintain the level of liquid inthe tank above the level of the first conduit port means 28 as will beexplained in detail later. In the embodiment shown in FIG. 1, secondconduit 22 describes a loop 29 which functions as a hydraulic balance onfirst filling of the tank.

The second conduit can include one or more second conduit port means 42to act as does the first conduit port means to preheat still further theliquid drawn from the lower portion of the tank for mixing in the finalmixing chamber.

Final mixing chamber 32 receives the now preheated liquid generally fromthe lower portion of the tank from the second conduit through secondconduit discharge 38. In addition, final mixing chamber 32 includes aheated liquid inlet port 44 as the principal means for drawing heatedliquid from the interior of the upper portion of tank 12. In thepreferred form of the present invention shown in FIG. 1, heated liquidinlet port 44 is vertically lower than first conduit port means 28. Thisarrangement allows the first conduit port means 28 to draw off forpreheating the hottest water which will normally collect near the liquidsurface 46, the interface between air cushion 48 and the liquid in thetank. Generation of the air cushion will be described later. Throughthis arrangement, the hottest water in the tank cannot communicatedirectly with the liquid discharge means 36.

The size of the first and second conduits, their inlets and outlets, aswell as the size of the first and second conduit port means such as 28and 42 and heated liquid inlet port 44 of final mixing chamber 32 can beselected and coordinated in size and location within the scope of thepresent invention to deliver heated liquid at a desired temperaturepartly as a function of incoming liquid temperature and pressure.

As shown by FIGS. 1 and 2, included within tank 10 generally in thelower portion is a heating means 50 such as heaters of the electricalresistance type commercially available. Also located within the tankgenerally in the lower portion is a temperature sensing means 52 such asa commercially available adjustable thermostat. Because of the relativesmall size of tank 10, it is preferable that the temperature sensingmeans 52 be of a type which senses and preferably integrates temperatureover a substantial portion of the tank rather than at a single point.Thus, thermostat 52 is shown to extend approximately one-third of thedistance between lower wall 18 and upper wall 16. Greater extensioncould be made if the vibration of such a temperature sensing means wouldnot present problems in vehicular operation.

Heating means 50 and temperature sensing means 52 are connected togetherand to a source of electrical power (not shown) through electricalconductors 54 so that the temperature sensing means 52 controls theoperation of heating means 50 as a function of the temperature of theliquid in the tank 10 in a manner which is well known in the art. Anovertemperature sensing device (not shown) can be mounted in the upperportion of the tank to sense temperature at the top of the tank and toshut off power to heating means 50 in the event of failure oftemperature sensing means 52.

Because the apparatus of the present invention operates with an aircushion 48 adjacent upper wall 16 of upper portion 11, it is preferredto include a pressure relief valve through a wall of the tank. Onearrangement, shown in FIG. 1 includes pressure relief valve 56 throughthe upper wall 16 of the tank. However, such a pressure relief valvecould be mounted elsewhere through the wall of the tank if desired andconvenient.

When the apparatus of the present invention is mounted for operation,liquid inlet means 34 is connected to a source of liquid, such as water,(not shown). Also, liquid discharge means 36 is connected with a valvemeans (not shown) such as the faucet of a lavatory wash basin or otherliquid dispensing unit. Thus cooperating with the apparatus of thepresent invention are valve means (not shown) which control liquid inletand discharge flow to and from the apparatus.

As shown in FIG. 1, there can be included in the apparatus of thepresent invention an electrical power control means such as button 58and control switch 59 which initiates operation of the heating means 50and temperature sensing means 52.

Although tank 10 is shown in FIG. 1 substantially as rectangular, itshould be understood that tank 10 can be provided in a variety of shapesand sizes desired for the particular application provided therelationships between the components defined by the present inventionare maintained. One typical size in the configuration shown in FIG. 1has a liquid capacity of about 3-5 pints.

When placed in operation, tank 10 is connected with means to introduceliquid into the tank and means to discharge liquid from the tank throughinlet 34 and discharge means 36, respectively. Then the valvecooperating with liquid discharge means 36 is opened. Liquid, such aswater, begins to fill the tank expelling air through the liquiddischarge means until the level of liquid in the tank covers heatedliquid inlet port 44. At that point at which liquid begins to flowthrough the liquid discharge means 36, the valve cooperating with suchdischarge means generally is closed, either automatically as with afloat-type valve or manually. Also, in the embodiment of FIG. 1, liquidtraverses the hydraulic balancing loop 29. If such valve is not closed,partial pressurization of air entrapped in the upper portion of the tankoccurs until the liquid level reaches liquid level control vent 40 atwhich time full pressurization of entrapped air occurs. Normally,however, when liquid begins to flow through the liquid discharge means,the valve associated with that means is closed to control moreaccurately the level of liquid in the tank and the amount of air cushionentrapped in the upper portion adjacent the wall 16.

Incoming liquid continues to fill the tank until it has compressed theair in the upper portion of the tank to a point at which the pressureexerted by the air being compressed and the pressure exerted by theincoming liquid are equal or at equilibrium. In one typical example,such pressure is at about 15 psi. and the flow rate is at about 1 gallonper minute.

' Thus there is established a liquid surface 46 as the interface betweenair cushion 48 and the liquid in the tank. The level of such a surfaceis controlled by the position of liquid minimum level control vent 40which will draw off air from the air cushion in the event the level 46falls below the level of vent 40. However, the level of liquid surface46 can be above control vent 40, dependent upon the pressure equilibriumbetween the liquid and the air in the air'cushion. Thus accord ing tothe present invention, control vent 40 in the second conduit must be ata vertically higherlevel than port means 28 in the first conduit inorder to maintain first conduit port means 28' immersed in heatedliquid. With this arrangement, pumping means 26 can operate continuouslyto draw heated water through first conduit port means 28 in order topreheat incoming liquid through first conduit 20 prior to its dischargethrough first conduit outlet 24 in the lower portion of the tank.

In the preferred arrangement shown in FIG. 1, first conduit port means28 is located vertically higher in the upper portion of the tank than isheated liquid inlet port 44. Thus the hottest water in the tank whichcollects in the area of liquid surface 46 is not discharged into thefinal mixing chamber 32 through inletport 44. It is drawn off throughfirst conduit port means 28 to be used to preheat incoming liquid infirst conduit 20. This arrangement not only increases the temperature ofsuch incoming liquid but also assists in the heating of the lowertemperature liquid after it is discharged through first conduit outlet24 and it rises through relatively cooler liquid in the tank.

The action of circulating the hottest tank liquid with the incomingliquid reduces the heating cycle time requiredby the heating means 50.Also, such action maintains overall tank temperature uniformity forquicker recovery after liquid is drawn from the tank. In addition, aswas mentioned before, any pressurized air introduced with the incomingliquid cannot pass directly into mixing chamber 32. Hence such aircannot pass directly through a shutoff faucet or valve generallyassociated with liquid discharge means 36.

As was mentioned before, the function of pumping means 26 in firstliquid carrying conduit 20 is to draw heated liquid through firstconduit port means 28. It will be understood that this function can beaccomplished through a variety of arrangements which create at least apartial vacuum or area of lower pressure within conduit 20 in thevicinity of port means 28. Thus liquid will flow preferentially from thetank through port means 28 into the interior of conduit 20 to mix withand increase the temperature of incoming liquid carried by conduit 20for introduction into interior of tank 10.

Several useful examples of pump means 28 are shown in FIGS. 3, 4 and 5.FIG. 3 represents a simple aspirator type arrangement to draw liquidinto conduit 20 through port 28. The use of a smaller diameter conduit27, as in FIG. 4, connected, such as by brazing within conduit 20 andincluding port means 28 creates a somewhat greater pressure droparrangement. The venturi of FIG. 5, created by swagging conduit 20 toreduce its diameter, includes port 28.

Although FIG. I shows the preferred relative positions of second liquidcarrying conduit discharge 38 into final mixing chamber 32 and itsheated liquid inlet port 44, it should be understood that a variety ofarrangements and positions can be maintained in order to adjust liquiddischarge. It is necessary, according to the present invention, thatliquid minimum level control vent 40 be maintained in a positionvertically higher than first conduit port means 28 and any other portcommu nicating with final mixing chamber 32, such as heated liquid inletport 44. However, as was mentioned before, significant advantages inefficiency and recovery time after liquid is drawn from the tank isachieved with relative positions as shown in FIG. 1. In thatarrangement, control vent 40 is at the highest vertical level and firstconduit port means 28 is vertically higher than heated liquid inlet port44.

In the use of apparatus according to the present invention andconstructed substantially as shown in FIGS. 1 and 2, inlet water atabout 25 p.s.i.g. and at a temperature of about 60 F was fed into a tankhaving a liquid capacity of about 5 pints. The desired outlettemperature was at a level no greater than 140 F and preferably at about125 F.

Tests on this apparatus within the scope of the present inventionresulted in more efficient performance, lower overall tank temperature,reduction by about 50 percent of the reheat recovery time and a shorterheating cycle. In addition, previously existing problems relating tosurging air pressure passing directly through the tank resulting in acondition of spraying air and water through the liquid discharge meanswas eliminated.

Iclaim:

1. An improved tank for heating and dispensing heated liquid, the tankbeing sealed except for the provision for liquid inlet and discharge andincluding:

an upper portion including an upper-wall;

a lower portion including a lower wall;

the tank during operation including an entrapped air cushion between theupper wall of the upper portion and the heated liquid to partiallycontrol movement of the liquid during operation and to allow forexpansion of the liquid by further compression of the air cushion if theliquid becomes frozen;

heating means in the lower portion of the tank;

temperature sensing means in the tank electrically connected with theheating means to control the heating means as a function of liquidtemperature in the tank; means to introduce liquid into the tank; and

liquid discharge means to discharge heated liquid from the tank; theimprovement comprising, in combination:

a first liquid carrying conduit connected through a wall of the tank tointroduce liquid into the tank;

a. the first conduit enclosed within the tank and extending into theupper portion and then into the lower portion and terminating in a firstconduit outlet within the tank generally directed toward and in spacedrelationship with the lower wall of the lower portion;

b. the first conduit having pumping means including a first conduit portmeans positioned in that portion of the first conduit located in theupper portion of the tank to draw heated water from the upper portion ofthe tank into the first conduit;

a second liquid carrying conduit enclosed within the tank;

a. the second conduit including a second conduit inlet in the lowerportion of the tank in spaced relationship with the lower wall of thelower portion;

b. the second conduit extending within the tank from its inlet in thelower portion into the upper portion of the tank and discharging into afinal mixing chamber;

0. the second conduit extending vertically higher into the upper portionthan the first conduit port means and including a liquid minimum levelcontrol vent through a wall of the second conduit and located verticallyhigher than the first conduit port means to maintain the level of theliquid in the tank above the level of the first conduit port means; and

a final mixing chamber located within the tank in the upper portion;

a. the mixing chamber connected with the second liquid carrying conduitto receive liquid from the conduit and connected with the liquiddischarge means; and

b. the mixing chamber including a heated liquid inlet port communicatingwith the upper portion of the tank to allow passage of the heated liquidfrom the tank into the mixing chamber to mix with cooler liquid from thesecond conduit prior to passage of liquid through the liquid dischargemeans.

2. The improved tank of claim 1 in which:

the first liquid carrying conduit is connected through a wall in thelower portion of the tank and extends in a loop from the lower portioninto the upper portion and then into the lower portion;

the second conduit inlet in the lower portion of the tank is adjacentthe first conduit outlet generally facing and in spaced relationshipwith the lower wall of the lower portion; and

4. The tank of claim 2 in which the first liquid carrying conduit isconnected through the lower wall and is connected with a first conduitauxiliary inlet and drain port directed to provide a portion of inletliquid generally along the lower wall.

1. An improved tank for heating and dispensing heated liquid, the tankbeing sealed except for the provision for liquid inlet and discharge andincluding: an upper portion including an upper wall; a lower portionincluding a lower wall; the tank during operation including an entrappedair cushion between the upper wall of the upper portion and the heatedliquid to partially control movement of the liquid during operation andto allow for expansion of the liquid by further compression of the aircushion if the liquid becomes frozen; heating means in the lower portionof the tank; temperature sensing means in the tank electricallyconnected with the heating meAns to control the heating means as afunction of liquid temperature in the tank; means to introduce liquidinto the tank; and liquid discharge means to discharge heated liquidfrom the tank; the improvement comprising, in combination: a firstliquid carrying conduit connected through a wall of the tank tointroduce liquid into the tank; a. the first conduit enclosed within thetank and extending into the upper portion and then into the lowerportion and terminating in a first conduit outlet within the tankgenerally directed toward and in spaced relationship with the lower wallof the lower portion; b. the first conduit having pumping meansincluding a first conduit port means positioned in that portion of thefirst conduit located in the upper portion of the tank to draw heatedwater from the upper portion of the tank into the first conduit; asecond liquid carrying conduit enclosed within the tank; a. the secondconduit including a second conduit inlet in the lower portion of thetank in spaced relationship with the lower wall of the lower portion; b.the second conduit extending within the tank from its inlet in the lowerportion into the upper portion of the tank and discharging into a finalmixing chamber; c. the second conduit extending vertically higher intothe upper portion than the first conduit port means and including aliquid minimum level control vent through a wall of the second conduitand located vertically higher than the first conduit port means tomaintain the level of the liquid in the tank above the level of thefirst conduit port means; and a final mixing chamber located within thetank in the upper portion; a. the mixing chamber connected with thesecond liquid carrying conduit to receive liquid from the conduit andconnected with the liquid discharge means; and b. the mixing chamberincluding a heated liquid inlet port communicating with the upperportion of the tank to allow passage of the heated liquid from the tankinto the mixing chamber to mix with cooler liquid from the secondconduit prior to passage of liquid through the liquid discharge means.2. The improved tank of claim 1 in which: the first liquid carryingconduit is connected through a wall in the lower portion of the tank andextends in a loop from the lower portion into the upper portion and theninto the lower portion; the second conduit inlet in the lower portion ofthe tank is adjacent the first conduit outlet generally facing and inspaced relationship with the lower wall of the lower portion; and theheated liquid inlet port of the mixing chamber is located verticallylower than the first conduit port means.
 3. The tank of claim 2 in whichthe second conduit includes a second conduit port means vertically lowerthan the heated liquid inlet port of the final mixing chamber to drawheated liquid from the tank into the second conduit.
 4. The tank ofclaim 2 in which the first liquid carrying conduit is connected throughthe lower wall and is connected with a first conduit auxiliary inlet anddrain port directed to provide a portion of inlet liquid generally alongthe lower wall.